Float valve

ABSTRACT

A float valve adapted for use in a toilet tank and which, in combination with a float arm and float, serves to control the refill level of water in that tank after the toilet has been flushed. The float valve is structured so that water flow therethrough is essentially noiseless from opening to closing of the valve; the valve&#39;&#39;s structure is such that more than one pressure drop is created within the valve housing to prevent any one pressure drop from inlet line pressure to tank pressure from being of a sufficient size to create water noise, and is such that chatter or fluttering of the valve is essentially eliminated as water flow through the valve is terminated. Further, the float valve is structured so that overflow of the toilet tank as a result of a leaky float ball is not possible; the valve closes due to water pressure in the inlet line when the tank has been refilled and the valve opens due to the float&#39;&#39;s weight as the tank is drained when the toilet is flushed.

United States Patent 1191 Hyde [ Sept. 25, 1973 FLOAT VALVE [75]Inventor: Robert W. Hyde, Crystal River, Fla.

[73] Assignee: Pryde Inc., Cincinnati, Ohio Primary Examiner-Martin P.Schwadron Assistant Examiner-David R. Matthews Atzo'rneyJohn W. Melvilleet al.

1 5 ABSTRACT A float valve adapted for use in a toilet tank and which,in combination with a float arm and float, serves to control the refilllevel of water in that tank after the toilet has been flushed. The floatvalve is structured so that water flow therethrough is essentiallynoiseless from opening to closing of the valve; the valves structure issuch that more than one pressure drop is created within the valvehousing to prevent any one pressure drop from inlet line pressure totank pressure from being of a sufficient size to create water noise, andis such that chatter or fluttering of the valve is essentiallyeliminated as water flow through the valve is terminated. Further, thefloat valve is structured so that overflow of the toilet tank as aresult of a leaky float ball is not possible; the valve closes due towater pressure in the inlet line when the tank has been refilled and thevalve opens due to the floats weight as the tank is drained when thetoilet is flushed.

12 Claims, 5 Drawing Figures PAIENTED 89251915 saw a 3 w N MW? w N 0 wM. W 8 \W F. 5 smmw an? W m m w K, M \R, NQ INN? YM B km. .Jlf N %\W Q;W a \w 5 %w m r. g m% m mm MJ w m R M n \N m A i- M Q E. 3 Q |l..| lHHHw MI IH I MIN MUM Hun k WW IIIR w lil w w 1%: Q Q v E w m ox m\ m N m\ QQM Q MM Q FLOAT VALVE This invention relates to valves. Moreparticularly, this invention relates to a float valve adapted for use ina toilet tank and which, in combination with a float arm and float,serves to control the refill level of water in that tank after thetoilet has been flushed.

Float valves of one type or another have, of course, been used for manyyears in conjunction with the refilling of toilet tanks. Basically, afloat valve functions to check the inlet flow of water from a watersource into the toilet tank until the toilet has been flushed, to allowwater flow into the tank after flushing the toilet, and to close offthat water flow after the refill level of the toilet tank has beenreached. The refill level of water in the toilet tank is regulated bythe vertical position of a sealed float ball connected through a floatarm to the float valves servo-mechanism. The float ball, being hollowand sealed to the atmosphere, rides on the water surface withinthetoilet tank. In operation, and upon flushing of the toilet, waterheld in the tank rushes out into the toilet bowl and this causes thefloat ball to fall. As the water level reaches the bottom of the tank aflush valve closes the tank and, thereby, reseals it from the toiletbowl. As the sealed float ball achieves its lower attitude on flushingof the toilet the float valve is opened to permit refilling of thetoilet tank, and as the sealedfloat ball achieves its upper attitudeafter refilling the toilet tank the float valve is closed to checkfurther inlet flow of water. Thus, the toilet tank is refilled afterflushing of the toilet.

A float valve is not a simple valve. A float valve must, of course, beable to control the flow of water to the toilet tank from a water sourceas the position of the sealed float ball dictates. But a float valvemust also be able to prevent water in the toilet tank from being drawnor siphoned back through the valve into the water supply if a vacuum isestablished on the valves inlet line. I

One typical float valve on the market today has a housing which definesa single valve chamber. The housing is connected to a water inlet pipethat opens into the chambers at an inlet port, and receives a valve stemthat extends vertically'into the chamber from the outside thereof. Awater outlet pipe also opens into the chamber. The valve stem isprovided with a head adapted to move vertically, as the stem movesaxially, into and out of sealing engagement with the chambers inletport. The valve stem is connected at one end to a lever arm, a floatball being connected to the lever arm s other end. The lever arm ismechanically linked to the valve housing and to the valve stem. Inoperation, as the float ball falls to its lowermost position in thetoilet tank upon flushing of the toilet, the valve stem is moved axiallyupward by the mechanical linkage and/or water pressure on the valve headto open the inlet port to the chamber and, thereby, supply water to theoutlet pipe to refill the tank. As the float ball reaches its uppermostposition in the tank after refilling, the mechanical linkage depressesthe valve stem axially downward toward the inlet port to close the inletport and, thereby, shut off the flow of water to the toilet tank. Toprovide an anti-siphon characteristic in this float valve, the floatvalve must be mounted in the toilet tank above the top water level inthe tank. The ceiling of the valve housing is provided with a series ofholes surrounding the valve stem, thereby essentially opening thechamber to the atmosphere. A deformable washer is also mounted to thevalve stem, the washer being positioned between the valve head and theceiling of the chamber when the float valve is closed. In operation, asthe valve stem moves up when the float ball has fallen due to flushingof the toilet, the deformable washer is pushed into sealing engagementwith the holes in the chamber ceiling to prevent substantial loss ofwater through those holes while refilling the toilet tank. When thetoilet tank is refilled and the float valve is closed, the chamber isopen to the atmosphere through the ceiling holes. In this attitude, andwhen water inlet line conditions are such that a vacuum is establishedin the inlet line, air is sucked into the valve chamber and into theinlet line instead of water in the toilet tank being siphoned back fromthe tank into the water supply. Prior art float valves which disclosethese characteristics are set out in U.S. Pat. No. 2,635,622 and U.S.Pat. No. 3,070,118.

Typically, and as is the case with the float valve structure describedin the paragraph above, the prior art float valve adapted for use in atoilet tank is opened either (l) by mechanically raisingor moving thevalve head off its seat to open the valve as the sealed float ball fallsor (2) by eliminating an abutment from the valve stem which keeps thevalve head seated on the inlet port so that the inlet line waterpressure raises the head off its seat to open the valve as the sealedfloat ball falls, thereby allowing the inlet flow of water into thetoilet tank for refilling the tank. Further, and typically, and as isthe case with the prior art float valve structure described above,closing of the float valve depends on the buoyancy of the sealed floatball to pivot the lever arm so that a mechanical linkage can depress thevalve stem to force the valve head to seat on the inlet port against theinlet pressure of the water supply, thereby checking the inlet flow ofwater to the toilet tank after the tank has been refilled.

The prior art float valves of the general type described above have acouple of drawbacks from the standpoint of practical operation in toilettanks. In the first instance such float valves are noisy. Noise in afloat valve occurs generally from at least one of two sources. The firstsource of float valve noise may arise because of partial vaporization ofthe water during refilling of the toilet tank, i.e., the forming ofbubbles in the water as the water passes through the valve seats orificeand, thereafter, the recapturing or dissolving of those bubbles backinto the water as the pressure on the outlet side of the orifice more orless equalizes. Such partial vaporization of water particularly occurswhen the water pressure differential or drop between the water inletline pressure and the toilet tank pressure is greater than about 40 psiand when that pressure drop occurs across a single orifice of a sizetypically found in float valves. The inlet water pressure to residentialhomes is anywhere from about 40 psi (in rural areas) to about psi (inmetropolitan areas); thus, the water noise problem is quite prevalent inmetrpolitan areas since prior art float valves provide only a singlepressure drop (from water inlet line pressure to toilet tank pressure)and since that drop is usually greater than 40 psi. The second source offloat valve noise may arise through chattering or fluttering of thevalves head when it closely approaches the final closed attitude withthe valves seat as the toilet tank approaches the final water refilllevel. In prior art float valves, as the float ball and lever arm moveup due to increasing refill depth of water in the toilet tank, thevalves head is brought in increasingly close proximity with the valvesseat. But this movement is relatively slow, i.e., the valves head doesnot move instantaneously between a totally open position and a totallyclosed position; as the orifice defined between the valves head and thevalves seat becomes of diminishing area, the water passing therethroughat water inlet line pressure tends to cause a high pitched or screechingsound, and/or tends to rattle or shake the valves servo-mechanism, allof which results in a chattering or fluttering noise until the valve istotally closed. Thus, in float valves of the prior art it is usually thecase that the water pressure provided by the source to the average homein most areas of this country is sufficiently great, if notsubstantially greater than, that pressure which will cause noise tooccur from either one or both of the above sources as the water flowsthrough the float valve into the toilet tank for refilling same.

In the second instance, the float valves of the prior art are notfailsafe as to closing in the sense that they usually depend on a floatball which is evacuated of atmosphere and is completely sealed to theatmosphere, i.e., the closing of a typical float valve depends on thebuoyancy of the float. This for the reason that the valves head ismechanically depressed by the pivoting lever arm as the float valverides up the water level during refilling of the toilet tank. When thewater level reaches the final refill level in the tank, the lever armhas mechanically depressed the valves head into sealing engagement withthe valves seat or inlet line port, If the float ball springs a leaksuch that it partially or completely fills with water, the float ballwill not ride up all the way with the water level as it rises in thetoilet tank, i.e., the float valve then will remain open even though thetoilet tank is refilled. Of course, such will result in an overflow ofthe toilet tank with its accompanying damage to the surrounding bathroomenvironment.

In the third instance, the float valve of that type described aboveprovides substantial maintenance problems over periods of prolonged use.When maintenance problems arise with prior art float valve structures,generally speaking the practical solution of the plumber is tocompletely replace the entire float valve, instead of repairing it,because of the complexity of the valve structure. Thus, problems inmaintenance of the valve are generally solved at the expense of theowner simply by installing a new valve instead of repairing the old one.

The float valve of this invention is adapted for use with a toilet tankto control the refill level of water in that tank after the toilet hasbeen flushed. The valve is connected to a float through a float arm, thefloat being adapted to ride on top the water surface in the tank. Thefloat valve is structured so that water flow therethrough is essentiallynoiseless from opening to closing of the valve; the valves structure issuch that at least one pressure drop is created within the valve housingto prevent any one pressure drop from inlet line pressure to tankpressure from being of a sufficient size to create water noise, and issuch that chatter or fluttering of the valve is essentially eliminatedas water flow through the valve is terminated. Further, the float valveis structured so that overflow of the toilet tank as a result of a leakyfloat ball is not possible since the float used need not be sealed inthe first instance but may be merely of an inverted cup-shapedconfiguration; the valve closes due to water pressure in the inlet linewhen the tank has been refilled and the valve opens due to the floatsweight as the tank is drained when the toilet is flushed.

The noiseless operation of the float valve is accomplished by more thanone pressure drop orifice in the valves housing through which the watermust flow from the water inlet line to the toilet tank so as to reducethe pressure of the inlet water in more than one step from the inletpressure level to the outlet pressure level. Two of these orifices maybe established by an open-close valve and a back pressure valve carriedin the valves housing. The increment of the pressure drops created ateach of the orifices is less than that which creates noise, i.e., lessthan 40 psi, thereby allowing the water flow through the valve to beessentially noiseless.

The float valve is designed to close due to water pressure, and open dueto the weight of the float, by providing an open-close valve thatincludes a flexible diaphragm (the valve head) which separates a sectionof the valves housing into a pilot chamber and a feed chamber; the pilotand feed chambers are related through a bleed port in the diaphragm, andthe water inlet line opens into the feed chamber. The diaphragmfunctions to close (when the valve is closed) and to open (when thevalve is open) a main port (the valve seat) by which water is allowed topass through the valve as the toilet tank is being refilled. Anauxiliary valve head is continually biased against a relief port in theflexible diaphragm and, in the float valve closed attitude, such causesthe diaphragm to seal off the main port. In operation, as the waterlevel in the toilet tank falls the float arm depresses the auxiliaryvalve heads stem, and this opens the relief port in the diaphragm toallow water in the pilot chamber to pass therefrom. Water in the feedchamber then is at a greater pressure than water in the pilot chamber,and this causes the flexible diaphragm to move to the open position(against the diaphragms normal closure bias) so that water can passthrough the main port to refill the toilet tank. As the tank refills thefloat arm is moved out of abutting engagement with the auxiliary valveheads stem because of the float riding up on the water surface, therebyallowing the relief port in the diaphragm to close in accord with itsusual closure bias and permitting inlet water pressure to bereestablished in the pilot chamber through the bleed port. The pressurearea of the diaphragm in the pilot chamber is preferably substantiallygreater than the pressure area of the diaphragm in the feed chamber;this insures that the diaphragm will seal off the main port after thetoilet tank is refilled since the water pressure in the pilot and feedchambers are equal as long as the relief port is closed by the auxiliaryvalve head.

Therefore, it has been one objective of this invention to provide afloat valve adapted for use in toilet tanks that is substantiallynoiseless in operation from opening to closing of the valve.

It has been another objective of this invention to provide a float valveadapted for use in toilet tanks which is constructed to a self-close dueto the inlet pressure of water to the valve when the tank is refilledand which is constructed to open due to the floats weight as the tank isdrained when the toilet is flushed.

It has been a further objective of this invention to provide a floatvalve adapted for use in toilet tanks which incorporates a novelservo-mechanism that cooperates with the float arm.

It has been yet a further objective of this invention to provide a floatvalve adapted for use in toilet tanks which is of modular construction,the main functioning parts of the valve being easily removable from thevalve housing, inlet piping and outlet piping, thereby allowing simplereplacement of a worn part within the valve housing to provide easy andinexpensive maintenance thereof.

Other objectives and advantages of the invention will be more apparentfrom the following detailed description taken in conjunction with thedrawings in which:

FIG. 1 illustrates the float valve of this invention in its operatingenvironment, namely, with a toilet tank and toilet bowl;

FIG. 2 is a perspective view illustrating the float valve with the floatarm, inlet piping, and outlet piping;

FIG. 3 is a partial cross-sectional view taken along lines 3-3 of FlG. 2illustrating the float valve in the closed attitude after the toilettank has been refilled;

FIG. 4 is a partial cross-sectional view similar to FIG. 3 illustratingthe float valve in the open attitude during refilling of the toilettank; and

FIG. 5 is a cross-sectional view taken along lines 55 of FIG. 3.

The float valve of this invention is adapted for use with a float arm 11and float 12, see FIG. 2. The environment within which the float valve10, float arm 11 and float 12 operate includes, of course, a toilet tank13 and a toilet bowl 14, see FIG. 1. Access to the inside of the toilettank 13 is provided through a toilet tank cover 15 that is removable.The float valve 10, float arm 11, and float 12 are adapted to cooperatewith flush valve structure, not illustrated, of any type well known tothe art, and the float valve is also adapted to cooperate with anafterfill tube 16 of that type well known to the art. In use, the toilet13, 14 is flushed in the usual manner, i.e., by turning handle 17; thiscauses the flush valve to open (which allows the water in the toilettank 13 to drain rapidly into the bowl l4) and then close, and causesthe float 12 to fall as the water level in the tank 13 recedes. As thefloat 12 falls to a lower position from an upper position the floatvalve 10 is opened (as will be subsequently explained in detail) toallow the tank 13 to be refilled. As the water level in the tankachieves the maximum refill depth 18 the float l2 rides thereon back'toits upper position at which the float valve is closed (as will besubsequently explained in detail) to close off or check the refill flowof water into the toilet tank, thereby controlling theflow and refilllevel of water in the toilet tank. General Structure The float valve 10is mounted on, and the float valves casing or housing 19 is moldedintegral with, a pipe structure 21 that defines a water inlet pipe 22and a water outlet pipe 23, see FIG. 2. A web 28 with reinforcing steps29 is provided between the outlet pipe 23 and the inlet pipe 22 so as tomaintain the rigidity of the pipe structure 21 which, along with valvehousing 19 is a one-piece molding.

The inlet pipe 22 has a flared collar 24, the pipe being threaded (as at25) below that collar. The pipe structure 21 is fixed in operatingrelation with a water source line (not shown) feeding the toilet tank 13by screwing the threaded section 25 of the inlet pipe 22 into the floor26 of the tank until collar 24 rests on the floor 26; thus, the collarserves to provide vertical stability to the float valve l0-pipe 21structure. It will be noted that the outlet 27 of the outlet pipe 23 ispositioned just above the collar 24. This allows water to be exhaustedfrom the outlet pipe 23 into the toilet tank 13 very close to the tanksfloor 26. Therefore, during most, if not all, of the refilling of thetoilet tank 13 the refill water is discharged into the tank below thewaters surface; such tends to muffle the noise during refill. Also, notethat the inlet pipe 22, which basically supports the float valve 10, isof sufficient height to position the float valve 10 above the refilllevel 18 of 'water in the toilet tank; such is important (as will besubsequently described in detail) in providing antisiphoncharacteristics for the float valve.

The float 12 is molded integral with the front end of the float arm 11,and is simply an inverted cup-shaped chamber open at the bottom 32. Whenthe water level rises to meet the float 12 as the toilet tank 13 isbeing refilled, the water itself entraps or seals air inside the floatsopen chamber 31. This provides the float 12 with the buoyancy requiredto permit it to ride up with the water level as the water levelcontinues to rise in the toilet tank 13 until the water level achievesthe refill depth 18.

The float arm 1 1 is pivotally mounted to an ear 33 extending from andfixed to the front face 34 of the float valve 10. The ear 33 presents apin 35 adapted to fit in holes defined by tongues 36 molded integralwith the rear end of the float arm 11. Thus, the float arm 11 isconnected to the float valve 10 for pivotal movement in a verticalplane.

It will be noted that the float arm 11 is pivotally connected to thefloat valve 10 above the valves stem 37, and that the float arm isprovided with a foot 38 that traces a diameter across the valves frontface 34 adjacent the point 35 of pivotal connection. The upper end ofthe foot 38, of course, mounts the tongues 36 and the lower end of thefoot 38 is molded integral with the float arm 11. A control screw 39 isthreaded through the foot 39 intermediate its length, the head of thecontrol screw being accessible for adjustment by a screwdriver and thebase of the control screw being engageable with a push'button 43 fixedto the exposed end of the valve stem 37; that is, the control screw 39is fixed to the foot 39 so that it is substantially axially alignedwith, but not in contact with, the valve stem 37 when the water level isat refill level 18. The function of the control screw 39 is to open thefloat valve 10 by depressing the valve stem 37 as the water level in thetoilet tank 13 recedes upon flushing the toilet 13, 14; once the floatvalve is opened water flows therethrough for refilling of the toilettank.

A limit screw 42 is threaded into the float arm 11 at a point on thefoot where the limit screws head can abut the rim 41 of the valveshousing 19 when the toilet tank 13 is substantially empty of water. Thelimit screw 42 is accessible for adjustment simply by pivoting the floatarm 11 vertically upward. The function of the limit screw 42 is to limitclockwise (as viewed in the drawings) pivotal motion of the float arm 11as the water level in the toilet tank recedes upon flushing the toilet13, 14, thereby preventing undue damage to the valves servo-mechanismfrom the weight of the float 12 and the float arm 11 once theservo-mechanism has been moved to the open attitude. Valve Structure Thefloat valve is provided with a cylindrical housing or casing 19 with theinlet pipe 22 and outlet pipe 23 radially intersecting same inapproximately the same plane, see FIGS. 3 and 4. The housing 19, incrosssection, is provided with a closed end 46 and an open end 47, i.e.,the housing is hollow when no component parts are located inside.

An outer tubular insert 48 is the first component located within thevalve housing during assembly, see P16. 3. The outer surface 49 of theouter tubular insert 48 is provided with a groove 50, the groove beinglocated between the inlet pipe 22 and the outlet pipe 23 when the insert48 is in place within the housing 19. The groove 50 receives an O-ring51, thereby closing off the inlet pipe 22 from the outlet pipe 23 exceptthrough the porting or orifices provided and described in detail below.

The outer tubular insert 48 includes a port wall 52 located between theinlet pipe 22 and outlet pipe 23 when the insert 48 is in place withinthe housing 19, the port wall 52 defining a first pressure drop orifice53 located axially of the housing. The first pressure drop orifice 53 isprovided with an annular boss 54 which defines a valve seat foropen-close valve 45. That portion of the housing 19 interior betweenclosed end wall 46 and port wall 52 is divided by a diaphragm or valvehead 44 for open-close valve 45. The diaphragm 44 is flexible and ishat-shaped in configuration, the outer periphery of the hat's brim 55being fixed or held against the closed end wall 46 of the housing 19;the brim 55 of the hat-shaped diaphragm 44 is provided with feet 56adapted to conform around an annular ledge 57 integral with tubular wallsection 58 of the outer tubular insert 48, thereby allowing thediaphragm 44 to be held against the closed end wall 46 of the housing19. Thus the hat-shaped diaphragm 44 and the first pressure drop orifice53 cooperate as the open-close valve 45, and the chamber 67 between theunderside 68 of the diaphragm 44 and the housings closed end wall 46 isessentially a pilot chamber.

The wall section 58 is cylindrical in configuration and is offsetinwardly from the outer surface 49 of the tubular insert so as to definean annular feed chamber 59 in combination with the valves housing 19.The feed chamber 59 surrounds the tubular insert 48 and is connectedwith a water supply source through inlet pipe 22 which intersectschamber 59 at 62. The feed chamber 59 is interconnected with a bafflechamber 63, which essentially is part of the feed chamber 59, by twoports 64 located at 180 relative one to the other about the periphery ofwall section 58. The baffle chamber 63 functions mainly to assure evenpressure distribution of water flowing into the valve 10 from inlet pipe22 about the top side 65 of the hat-shaped diaphragm 44. The pilotchamber 67 communicates with the baffle chamber 63 through at least onesmall bleed port 74 located in the brim 55 of the hat-shaped diaphragm44.

Preferably the outside diameter of the first pressure drop orifice 53and boss 54 relative to the brim 55 diameter of the hat-shaped diaphragm44 is such that only a minor surface 65 of the diaphragm 44 is presentedto water pressure in the baffle chamber 63, i.e., the pressure or forcearea on the baffle chamber side of the diaphragm 44 (for opposing thepressure area on the pilot chamber 67 side of the diaphragm 44) is onlyequal to brim area 65. On the other hand, a major surface area 68 of thediaphragm 44 is presented to water under pressure in the pilot chamber67, Le, the pressure or force area on the pilot chamber side of thediaphragm 44 (for opposing the pressure area on the baffle chamber 63side of the diaphragm 44) is equal to the brim area 65 and the crownarea 60.

The top side 65 of the hat-shaped diaphragm 44 is provided with anose-shaped relief port 66 located axially of the housing 19, the reliefport being axially aligned with first pressure drop orifice 53 definedin the port wall 52. The valve stem 37 is of a length such that itextends from the pilot chamber 67 to the front face 34 of the floatvalve 10 where it terminates in push button 43 that can be contacted bycontrol screw 39. The valve stem 37 is integral with a pilot head 72located within the pilot chamber 67, that pilot head being adapted toclose the relief port 66 in the hat-shaped diaphragm 44. Thus, the pilothead 72 (as the valve head) and relief port 66 (as the valve seat)define an auxiliary valve 71. The valve stem 37, through use ofcompression spring 73, is continually urged to the right as shown in theFigures (and, thereby, pilot head 72 is continually urged toward aclosure attitude with the relief port 66) to close the auxiliary valve71 unless float arm 11 has pivoted down so that control screw 39depresses the valve stem to the left (and, thereby, moves pilot head 72to an open attitude with the relief port 66) to open the auxiliary valve71 which occurs when the toilet is flushed.

In the float valve 10 closed attitude where water flow is checked orstopped, therefore, and as water is directed into the feed chamber 59,63 through inlet pipe 22, some of the water bleeds into the pilotchamber 67 through the bleed port 74. The pressure created on the majorforce area 68 of the diaphragm 44 from the pilot chamber 67, however, issubstantially greater than the pressure created on minor force area 65of the diaphragm from the feed chamber 59, 63 because of the differencein surface areas on which the water pressure acts; such a pressuredifferential, under equilibrium conditions and when the pilot head 72 isclosed against relief port 66, keeps the diaphragm 44 in the closedattitude relative to the valve seat 54 in main port wall 52. This, ofcourse, prevents water flow through the float valve 10 since the firstorifice 53 at valve seat 54 is closed. Thus, the open-close valve 45portion of the float valve 10 and, hence, the float valve itself, isclosed by water pressure of the inlet water, and not by mechanicallinkages actuated by the float arm 11.

The outer tubular insert 48 is adapted to cooperate with an innertubular insert 78, the inner tubular insert being coaxially positionedtherein during assembly and being seated at its inner end in recess 77of port wall 52. The inner tubular insert 78 is provided with a plate 79molded integral therewith that defines the valves front face 34 and thatserves to locate the inner insert in the outer insert 48 at plate 79end. The plate 79 also defines a series of air ports 76 which functionin a manner to be subsequently explained. The outer periphery 80 ofplate 79 defines a groove 81 adapted to receive foot 88 of an annulardonut-shaped diaphragm 82, the donut-shaped diaphragm being fixed inplace when the inner tubular insert 78 is assembled with the valveshousing 19 by locating foot 88 between the plate s outer periphery 80and the inside surface of housing 19. The donut-shaped diaphragm 82 isflexible and is adapted to flex into and out of engagement (compareFIGS. 3 and 4) with rim 83 presented by the forward tubular wall 70 ofthe outer tubular insert 48, the normal flexure attitude being a closedattitude as illustrated in FIG. 3. Thus, the donut-shaped diaphragm 82serves as a valve head, and the tubular walls rim 83 serves as a valveseat, to establish a back pressure valve 69 inside the float valve thatis directly connected with the outlet pipe 23. Further, the backpressure valve 69 allows discharged water flow into the outlet pipe 23through an annular or third pressure drop orifice 101, see solid lineposition of donut-shaped diaphragm in FIG. 4.

This back pressure valve 69 is, in a sense, a dual action valve in thatit also includes an annular nose portion 98 that cooperates with theinside surface 99 of face plate 79. This establishes an anti-siphonvalve 61 inside the float valve 10, the anti-siphon valve's head beingthe donut-shaped diaphragms nose portion 98 and the anti-siphon valvesseat being rim area 99 on the inner face 100 of the tubular insert 78.When a suction is established on inlet pipe 22, this anti-siphon valve61 allows only air from above the water refill level 18 in the toilettank 13 to be sucked back through the float valve, thereby insuring thatwater in the toilet tank 13 will not be sucked back through the outletpipe 23 and the float valve 10 into the water supply. Ifa vacuum orsuction is established on inlet pipe 22, nose portion 98 is deflectedaway from, i.e., sucked away from, contact with valve seat 99 so thatair can be drawn into the float valve 1 through air ports 76 in thefloat valves front face plate 79. Further, when the nose portion 98 ofthe diaphragm 82 is so deflected the outlet pipe 23 is sealed from thefloat valves interior by the back pressure valve 69 portion of thediaphragm. The antisiphon attitude of the diaphragm 82 is illustrated inphantom lines in FIG. 4.

The inner tubular insert 78 defines a first intermediate chamber 90 thatis cylindrical in configuration, and that is coaxial with the firstpressure drop orifice 53 in port wall 52 and with feed chamber 59, 63.This first intermediate chamber 90 is provided with a passage 91 at itsother end that is coaxial with main port 53. A second pressure droporifice in the form of two rectangular orifices 96 are provided in thefirst intermediate chamber 90 in the middle thereof, i.e., in the sidewalls of that chamber, opposite one from the other. These ports ororifices 96 provide passageways between the first intermediate chamber90 and a second intermediate chamber 97 in the float valve 10. Thesecond intermediate chamber 97 is a concentric, annular chamber that isdefined along its side walls by the outer tubular insert 48 and theinner tubular insert 78, is closed at one end by the port wall 52, andcooperates with the back pressure valve 69 at the other end. Thus, themain water flow through the float valve 10 proceeds from inlet pipe 22into feed chamber 59, 63, through first pressure drop orifice 53, intofirst intermediate chamber 90, through second pressure drop orifices 96,into second intermediate chamber 97, through third pressure drop orifice101, through annular exha ust chamber 89, and into outlet pipe 23.

The valve stem 37 passes through passage 91 and terminates in pushbutton 43 located outside the valves housing 19. The push button 43 isT-shaped in crosssection, and includes a sleeve 92 by which the buttonis fixed to the valve stem 37. The passage 91 in the plate 79 isconfigurated to cooperate with the sleeve 92 to aid in guiding the valvestem 37 in its reciprocal motion back and forth between the openattitude and closed attitude as will be subsequently explained. Thecompression spring 73 is positioned to bear between the underside of thepush button 43 and the valves front face 34, thereby continuously urgingthe valve stem 37 toward the right as illustrated in the figures(thereby, continuously urging the pilot head 72 toward the major surfacearea 68 of the hat-shaped diaphragm 44). A packing ring 93 is fixed onthe valve stem 37 between a stop 94 mounted to the valve stem and thebottom of the push buttons sleeve 92. The packing ring 93 is providedwith flexible annular walls 95, the packing ring functioning to preventspitting of water through the passage 91 in the plate 79 as water flowsthrough the first intermediate chamber 90. Note particularly that valvestem 37 is carried by, and located within the float valve 10 by virtureof, packing ring 93 and hatsahped diaphragm 44. Since both the packingring 93 and hat-shaped diaphragm 44 are flexible they are convenientlymade of a relatively high energy absorbing material, e.g., rubber; thistends to damp out vibrations of the valve stem 37 as water flows throughthe valve (and particularly is this so as the hat-sahped diaphragm 44moves toward closure attitude shown in FIG. 3 from the open attitudeshown in FIG. 4 as the maximum refill depth is approached during fillingof the toilet tank) and, thereby, tends to reduce noise during refillingof the toilet tank.

The inner tubular insert 78 and the outer tubular insert 48 are held incoaxial assembly within the valve housing 19 by means of finger locks 84inserted through notches 85 in the housing, see FIG. 5. The finger locks84 are in the nature of arcuate bars 86 each of which partlycircumscribes the outer periphery of the housing, the bars 86 eachpresenting two locking fingers 87 fixed thereto and adapted to beinserted into the interior of the housing through the notches 85. Whenthe finger locks are in position they press the tubular inserts 48, 78toward the closed rear wall 46 of the housing 19, thereby maintainingthe float valve 10 inv operating assembly.

The after-fill tube 16 is tapped into water exhaust chamber 89 as at102. The after-fill tube 16 is of a small diameter relative to thediameter of water outlet pipe 23 and it feeds overflow tube 102 that isfixed to the floor 26 of the toilet tank 13. The after-fill tube 16functions as is well known to the art, to tap off a small quantity ofwater flowing through the float valve 10 as the toilet tank 13 is beingrefilled, that water being directed through overflow tube 102 into thebowl 14 of the toilet to refill the bowl at the same time the tank isbeing refilled.

In operation, and under those conditions which obtain when the toilettank 13 is full of water to refill level 18, the attitude of the floatvalve 10 is closed as is illustrated in FIG. 3; in this attitude nowater flows through the float valve. In the closed attitude, and atrefill level 18 in the tank 13, float 12 has caused float arm 11 topivot counterclockwise (as viewed in the Figures) until control screw 39is removed from contact with push button 43; this allows valve stemspilot head to maintain closure or sealing contact with relief port 66 inthe diaphragm 44 due to compression spring 73. Further, in the closedattitude water from inlet line 22 is in the feed chamber 59, 63 and thepilot chamber 67 (having entered through bleed port 74) with the waterpressure in those chambers being substantially equal because the watercannot escape from the pilot chamber as relief port 66 is sealed. Butthe total force exerted on the pilot chamber 67 side of the hat-shapeddiaphragm 44 by the water present in the pilot chamber 67 issubstantially greater than the total force exerted on the feed chamber59, 63 side of the diaphragm 44 by the water present in the feed chamberbecause only a minor surface area 65 is exposed to the water pressure inthe feed chamber and a major surface area 68 is exposed to the waterpressure in the pilot chamber; this causes the diaphragm 44 to seatagainst the boss 54 on the main port wall 52, thereby closing off firstpressure drop orifice 53 and outlet pipe 23 from the water source andinlet pipe 22. It is emphasized that float valve is maintained in theclosed attitude, and is in fact closed, by virtue of the water pressurein the inlet pipe 22 acting on the major surface 68 of the diaphragm 44in the pilot chamber 67 when the control screw 39 is moved out ofcontact with the valve stems push button 43. Further, it is emphasizedthat the float arm 11 itself does not close the float valve 10, i.e.,there is no mechanical linkage between the float arm 10 and theopen-close valve 45 which causes the diaphragm 44 to seat against theboss 54 in the port wall 52.

When the handle 17 on the toilet tank 13 is rotated to flush the toiletbowl 14, water is rapidly drained from the toilet tank 13. As waterdrains from the toilet tank 13 the float arm 11 pivots clockwise asillustrated in FIG. 2, thereby bringing the control screw 39 intocontact with the valve stems push button 43 to open the float valve 10.As the float arm continues to pivot clockwise due to the falling floatl2, and until the head of limit screw 42 abuts rim 41 of the floatvalves housing 19, the valve stem 37 is moved axially toward the left asillustrated, compare FIGS. 3 and 4. This opens relief port 66 betweenthe pilot chamber 67 and the first intermediate chamber 90, therebypermitting high pressure water in the pilot chamber to drain into thefirst intermediate chamber 90. This creates a substantial pressuredifferential between the feed chamber 59, 63 and the pilot chamber 67,the pressure in the feed chamber being substantially higher because ofthe high rate water flow thereto at inlet linepressures from the inletpipe 22, and the very low rate water flow into the pilot chamber 67through the bleed port 74. In turn, this high pressure condition is thefeed chamber 59, 63 in combination with the low pressure condition inthe pilot chamber 67 causes the diaphragm to collapse toward the closedend 46 of the valves housing 19, i.e., move toward the left asillustrated in the Figures. The difference in the diaphragm force area68 in the pilot chamber 67 and the opposing force areas 60 and 65 issufiicient to permit collapsing of the diaphragm 44 at this point. This,of course, opens first orifice 53 in the port wall 52 and allows waterfrom the feed chamber 59, 63 to pass through the float valve 10. As longas the valve stem 37 is depressed into that attitude illustrated in FIG.4 (which will be the case at least until the refill level contacts thebottom of float 12) an open equilibrium condition is created for waterflow through the float valve 10, the valve being held open in the samemanner by which it is opened in the first instance.

After the main valve 45 is opened, water passes from the feed chamber59, 63 into the first intermediate chamber 90. It will be particularlynoted that a radial water flow to the feed chamber 59, 63 and into thefirst pressure drop orifice 53 is transposed into a longitudinal waterflow within the first intermediate chamber toward the packing ring 93,thereby aiding in the creation of a pressure drop in the water as itmoves between the inlet and outlet of this first intermediate chamber.

From the first intermediate chamber 90 the water flows out through thetwo side wall orifices 96 (i.e., the second pressure drop orifice) intothe second intermediate chamber 97, see FIG. 4. It will be recalled thatthe annular donut-shaped diaphragm 82, in its closed attitude asillustrated in FIG. 3, is such that the central portion or web thereofis seated against the rim 83 of the outer tubular insert 48, therebyclosing the outlet pipe 23 to the second intermediate chamber 97. Butas.

water enters the second intermediate chamber 97 from the firstintermediate chamber 90 through ports 96, the pressure thereof causesthe diaphragm 82 to deform into that attitude illustrated in solid linesin FIG. 4. This, of course, opens the third pressure drop orifice 101(which is directly connected with outlet pipe 23 through annular exhaustchamber 89), thereby providing valving by which the water is admitted tothe outlet pipe from the second intermediate chamber into the toilettank 13 for refilling same.

One particular novel characteristic of this float valve 10 is itsability to damp or eliminate the noise usually generated in toilet tankfloat valves. The chatter or flutter source of water noise issubstantially eliminated because valve heads 44, 82'are of a resilient,sound dam pening character, e.g., rubber or the like, and because valvestem 37 is essentially encased and carried by rubber sleeves in the formof apertured relief port 66 in the diaphragm 44 and packing ring 93. Thevaporization source of water noise is controlled by providing a seriesof three controlled pressure drops over the three pressure drop orifices53, 96, and 101, the water pressure in the inlet pipe 22 being reducedto atmospheric pressure in the toilet tank 13 in three stages. The threefunctional orifices over which the three step pressure drop occursinclude, in sequence, (a) that orifice 53 defined by hat-shapeddiaphragm 44 and valve seat 54 in the main port wall 52 (this orificebeing a variable orifice) i.e., the open-close valves 45 orifice; (b)the two fixed dimension orifices 96 in the side wall of the firstintermediate chamber 90; and (c) that orifice 101 between valve seat 83on the outer tubular insert 48 and the flexible donut-sahped diaphragm82 (this also being a variable valves 69 orifice), i.e., the backpressure valve '5 orifice. Generally speaking, the water pressuresupplied to the homeowner is in a range anywhere from about 40 psig toabout 90 psig; the lower water pressure ranges are usually found inrural areas, and the higher water pressure ranges are generally found incity areas. Further, the flow of water through an orifice at such a rateand pressure which establishes a pressure drop across that orifice ofgreater than about 40 psi will cause noise. Consequently, and if thepressure drop over each of the three orifices remains less than 40 psi(as is possible where three orifices are provided as disclosed herein),there will be no noise generated in the float valve because the audibleand undesirable noise level is generally found where there is a pressuredrop of 40 psi or greater.

the side wall orifices 96 in the first intermediate chamber 90. Further,the pressure drop is controlled over the first orifice 53 because radialwater flow from the main port 22 is transposed into longitudinal waterflow which is braked by the packing ring 93, the water flow beingreversed before it can pass through the side wall orifices 96 of thefirst intermediate chamber 90. As a general rule, and for a givenorifice 53 size in the port wall 52, a decrease in the orifice 96 sizein the first intermediate chamber 90 will increase the back pressureand, thereby, act to lessen the pressure drop of the water as it flowsthrough the first orifice 53. Therefore, the orifice 96 size in thefirst intermediate chamber 90 should be such to assure that the pressuredrop through the first pressure drop orifice 53 is not greater thanabout 40 psi.

Further, the donut-sahped diaphragm 82 cooperates with the secondpressure drop orifices 96 of the first intermediate chamber 90 to insurethat the pressure drop through the orifices 96 is not greater than 40psi. As with the function of the orifices 53 in the first pressure dropchamber 90, the flexible donut-shaped diaphragm 82 creates a backpressure on the water within the secnd intermediate chamber 97 tocontrol the pressure drop created as the water passes through orifices96. The back pressure established by the back pressure valve 69, i.e.,the pressure required to open the third pressure drop orifice 101, canbe varied by varying the thickness of the diaphragm 82, thecross-sectional shape of the diaphragm 82, or the durometer of theflexible material used. The higher the durometer or the thicker thedonut-shaped diaphragm 82 in that shape shown, the greater will be thepressure required to open the third orifice 101 and the less will be thepressure drop across orifices 96. Since there is no back pressure on thethird orifice 101, the water pressure must be below about 40 psi whenthe water starts to pass through that orifice so that no noise iscreated as it passes therethrough and, of course, such is the casebecause of the pressure drops created at the first 53 and second 96orifices. Thus, water passes from the inlet pipe 22 through the floatvalve and out the outlet pipe 23 into the toilet tank 13 with nopressure drop at any of the three orifices 53, 96, or 101 greater thanabout 30 psi if the inlet water pressure is no greater than about 90psi; 90 psi, it will be recalled, is about the highest water pressurefor home use ever observed in the majority of the areas of this country.

Continuing with the operation of the float valve 10, air is entrapped inthe float 12 by the rising water as the toilet tank 13 is refilled withwater after flushing the bowl 14, thereby creating a buoyant float whichwill ride up on the water. As the float 12 rides up on the water thecontrol screw 39 is moved out of contact with the valve stems pushbutton 43, thereby permitting the spring 73 to maintain the valve stemspilot head 72 into sealing contact with the relief port 66 in thehatshaped diaphragm 44. When this occurs water that is bleeding from thefeed chamber 59, 63 into the pilot chamber 67 through the bleed port 74is captured and retained in the pilot chamber. As the pilot chamber 67fills once again with water, the pressure exerted on the pilot chamber67 side of the diaphragm 44 becomes substantially greater than thepressure exerted on the feed chamber 59, 63 side of the diaphragmbecause of the difference in the diaphragm force areas 68, 65 presentedin each of those chambers. This causes the diaphragm head 44 to moveaxially toward the right, as illustrated in FIG. 4, to close the orifice53 in the port wall 52 of the float valve, i.e., to cause the valvesservo-mechanism to once again achieve the closed attitude as illustratedin FIG. 3. This, of course shuts off 1 water flow through the floatvalve 10. The bleed port 74 size controls the rate of closing theorifice 53 by diaphragm 44. Thus, it is particularly noted that thefloat valve is opened due to the weight of the float 12 which, as itfollows the water level down when water is being drained from the toilettank 13 into the toilet bowl 14 upon flushing the toilet, finally abutsthe valve stems push button 43 and causes the open-close orifice 71 toopen. Further, the float valve 10 closes simply by removing the controlscrew 39 abutment from'the valve stems push button 43 to allow theauxiliary valve 71 to remain closed, and to allow water pressure toforce the diaphragm 44 against boss 54, all in the manneraforedescribed.

It is possible under certain float valve 10 operating conditions for asuction to be established in the water inlet pipe 22. The problemassociated with float valves that do not have an anti-siphoncharacteristic is that the water in the toilet tank will be sucked backup the outlet pipe, through the float valve, and back into the watersupply when a suction is established in the inlet pipe. Such woulddefinitely provide health hazards to the general public in thatcontamination of the water supply is possible by this route if anycontaminants or the like are in the toilet tank when this contingencyarises. Hence, it is common for municipal codes to require that floatvalves have an anti-siphon characteristic. As noted, this particularfloat valve 10 is mounted above the refill level 18 of the water in thetoilet tank 13, and must be so mounted for the anti-siphon structure tobe fully operative. When a suction is established on the inlet pipe, andas illustrated in phantom lines in FIG. 4, the flexible donut-shapeddiaphragm 82 is sucked toward the closed end 46 of the valves housing19. This assures that the outlet pipe 23 is sealed from secondintermediate chamber 97 and, hence, from the inlet pipe 22. Further,this causes the nose 98 of the donut-shaped diaphragm 82 to deflectinwards and open an annular port to the atmosphere through air ports 76in the face plate 79. Because air ports 76 in the plate 79 are alwaysopen to the atmosphere when the nose 98 of the diaphragm 82 is asillustrated in phantom in FIG. 4 (due to the suction present in theinlet pipe 22), the atmosphere is open to the inlet pipe and onlyatmosphere is sucked through the float valve 10. That is, because thefloat valve 10 is mounted above the refill level 18 of the water in thetoilet tank 13, when a suction is established on the inlet pipe 22 thereis nothing but air sucked through the float valve 10 back to the watersupply. Thus, no water from the toilet tank 13 can be siphoned back intothe inlet pipe 22, and back to the supply source.

It will be noted that the structure of this float valve 10 unit iscomprised of replaceable cartridge parts within the valves housing 19,and that the float valve can be repaired while mounted within the toilettank. That is, the only thing that need be done to provide maintenanceto the float valve 10, or indeed to provide an entire newservo-mechanism and valve structure inside the housing 19, is simply toremove the locking fingers 87 from the housing and slip out the inner 78and outer 48 tubular inserts. Thereafter, new inserts, diaphragms,spring, packing ring and/or valve stem need merely be installed orassembled with the housing to once again make the float valve 10operational. This modular construction, of course, reduces maintenancecosts to the homeowner.

Having described in detail the preferred embodiment of my invention,which I desire to claim and protect by Letters Patent is:

l. A float valve used in combination with a float arm and float inside atoilet tank, said float valve comprising a housing interconnected with awater inlet pipe and a water outlet pipe,

a flexible diaphragm having a permanently open bleed port therein andbeing fixed in said housing so as to divide at least a section thereofinto a feed chamber and a pilot chamber, said inlet pipe beinginterconnected with said feed chamber, and said bleed port allowingwater to bleed into said pilot chamber from said feed chamber,

a wall of said feed chamber having structure that defines a main portopening into an intermediate chamber, interconnected with said outletpipe, said main port being adapted for closure by said diaphragm toclose off the flow of water through the float valve, and

a valve stem extending into said pilot chamber, said valve stem mountinga pilot head inside of said pilot chamber and said pilot head beingadapted to cooperate with a relief port defined in said diaphragm toopen and close same depending on the water level in the toilet tank,said relief port extending between said pilot chamber and saidintermediate chamber,

the float arm being associated with said valve stem so as tocause saidpilot head to close said relief port when the refill level of the toilettank has been reached and to open said relief port as the toilet tank isdrained, the water pressure in said feed chamber causing said diaphragmto flex away from said main port and open the float valve when saidrelief port is first opened, and the water pressures in said feed andpilot chambers allowing said diaphragm to seal said main port and closethe float valve when said relief port is closed.

2. A float valve as set forth in claim 1 wherein the force area of saiddiaphragm in said pilot chamber is substantially greater than the forcearea of said diaphragm in said feed chamber, thereby causing thediaphragm to flex into sealing contact with said main port when saidrelief port is closed by said pilot head and when the water pressure issubstantially equal in the feed and pilot chambers.

3. A float valve as set forth in claim 1 including an anti-siphon valvebetween said intermediate chamber and said outer pipe, said anti-siphonvalve allowing air to be sucked through said float valve into said inletpipe when a vacuum is established on said inlet pipe, and said floatvalve being positioned above the refill water level in said toilet tank.

4. A float valve as set forth in claim 1 wherein said feed chamber isannular in configuration and surrounds a concentric baffle chamber thatdirectly cooperates with said flexible diaphragm, said feed chambercollecting water presented by said inlet pipe and distributing saidwater evenly on the feed chamber side of said diaphragm by use of saidbaffle chamber.

5. A float valve as set forth in claim 1 including a spring loading onsaid valve stem, said spring loading normally urging said pilot headinto sealing contact with said relief port when the toilet tank isrefilled, and said valve stem being depressed by a control device fixedto said float arm so as to open said relief port as said float arm fallsduring draining of said toilet tank.

6. A float valve as set forth in claim 1 wherein said inlet pipe, floatvalve housing, and outlet pipe are of a one-piece plastic molding, saidinlet pipe being of at least sufficient length to locate the float valveabove the refill level of said tank, and said outlet pipe extending downfrom the float valve a sufficient length to allow its terminationadjacent the floor of said toilet tank.

7. A float valve as set forth in claim 1 including a back pressure valveat the outlet of said intermediate chamber, said back pressure valveserving to create a back pressure on the water flow through said mainport to control the pressure drop through that main port.

8. A float valve as set forth in claim 7 wherein said back pressurevalve is comprised of a flexible diaphragm adapted to flex between afirst attitude where said outlet pipe is closed relative to said mainport and a second attitude where said outlet pipe is open relative tosaid main port, said back pressure diaphragm being closed when no wateris flowing through the float valve and being open when water is flowingthrough the float valve.

9. A float valve as set forth in claim 8 wherein said back pressurediaphragm is also adapted to flex into a third attitude where it opensair ports in said housing to said main port, said diaphragm being flexedto this third attitude when a vacuum is established on said inlet pipeso that air can be sucked through said float valve.

10. A float valve as set forth in claim 9 wherein said back pressurediaphragm seals off said outlet pipe as well as opens said air portswhen in its third attitude, seals off said air ports and opens saidoutlet pipe to said main port in its second attitude, and seals bothsaid outlet pipe and said air ports from said main port in its firstattitude.

11. A float vavle as set forth in claim 7 including structure withinsaid housing defining two intermediate chambers into which water flowfrom said main port is discharged the water flowing from said main portinto said first intermediate chamber and then through said secondintermediate chamber in sequence, and said back pressure valve beinglocated at the outlet of said second intermediate chamber, and

at least one orifice communicating between said first and secondintermediate chambers to allow water flow therebetween, said portproviding a third pressure drop orifice in addition to the pressure droporifices provided at said main port and back pressure valve so thatwater noise is substantially eliminated as water flows through the floatvalve.

12. A float vavle as set forth in claim 11 wherein said two tubularintermediate chambers are located axially and concentrically within saidhousing, the water flow to said main port being in an annular flow whichis transformed to a longitudinal flow after it passes through said mainport, and the water flow to said back pressure valve being alongitudinal flow which is transformed into an annular flow as itexhausts from said back pressure valve.

1. A float valve used in combination with a float arm and float inside atoilet tank, said float valve comprising a housing interconnected with awater inlet pipe and a water outlet pipe, a flexible diaphragm having apermanently open bleed port therein and being fixed in said housing soas to divide at least a section thereof into a feed chamber and a pilotchamber, said inlet pipe being interconnected with said feed chamber,and said bleed port allowing water to bleed into said pilot chamber fromsaid feed chamber, a wall of said feed chamber having structure thatdefines a main port opening into an intermediate chamber, interconnectedwith said outlet pipe, said main port being adapted for closure by saiddiaphragm to close off the flow of water through the float valve, and avalve stem extending into said pilot chamber, said valve stem mounting apilot head inside of said pilot chamber and said pilot head beingadapted to cooperate with a relief port defined in said diaphragm toopen and close same depending on the water level in the toilet tank,said relief port extending between said pilot chamber and saidintermediate chamber, the float arm being associated with said valvestem so as to cause said pilot head to close said relief port when therefill level of the toilet tank has been reached and to open said reliefport as the toilet tank is drained, the water pressure in said feedchamber causing said diaphragm to flex away from said main port and openthe float valve when said relief port is first opened, and the waterpressures in said feed and pilot chambers allowing said diaphragm toseal said main port and close the float valve when said relief port isclosed.
 2. A float valve as set forth in claim 1 wherein the force areaof said diaphragm in said pilot chamber is substantially greater thanthe force area of said diaphragm in said feed chamber, thereby causingthe diaphragm to flex into sealing contact with said main port when saidrelief port is closed by said pilot head and when the water pressure issubstantially equal in the feed and pilot chambers.
 3. A float valve asset forth in claim 1 including an anti-siphon valve between saidintermediate chamber and said outer pipe, said anti-siphon valveallowing air to be sucked through said float valve into said inlet pipewhen a vacuum is established on said inlet pipe, and said float valvebeing positioned above the refill water level in said toilet tank.
 4. Afloat valve as set forth in claim 1 wherein said feed chamber is annularin configuration and surrounds a concentric baffle chamber that directlycooperates with said flexible diaphragm, said feed chamber collectingwater presented by said inlet pipe and distributing said water evenly onthe feed chamber side of said diaphragm by use of said baffle chamber.5. A float valve as set forth in claim 1 including a spring loading onsaid valve stem, said spring loading normally urging said pilot headinto sealing contact with said relief port when the toilet tank isrefilled, and said valve stem being depressed by a control device fixedto said float arm so as to open said relief port as said float arm fallsduring draining of said toilet tank.
 6. A float valve as set forth inclaim 1 wherein said inlet pipe, float valve housing, and outlet pipeare of a one-piece plastic molding, said inlet pipe being of at leastsufficient length to locate the float valve above the refill level ofsaid tAnk, and said outlet pipe extending down from the float valve asufficient length to allow its termination adjacent the floor of saidtoilet tank.
 7. A float valve as set forth in claim 1 including a backpressure valve at the outlet of said intermediate chamber, said backpressure valve serving to create a back pressure on the water flowthrough said main port to control the pressure drop through that mainport.
 8. A float valve as set forth in claim 7 wherein said backpressure valve is comprised of a flexible diaphragm adapted to flexbetween a first attitude where said outlet pipe is closed relative tosaid main port and a second attitude where said outlet pipe is openrelative to said main port, said back pressure diaphragm being closedwhen no water is flowing through the float valve and being open whenwater is flowing through the float valve.
 9. A float valve as set forthin claim 8 wherein said back pressure diaphragm is also adapted to flexinto a third attitude where it opens air ports in said housing to saidmain port, said diaphragm being flexed to this third attitude when avacuum is established on said inlet pipe so that air can be suckedthrough said float valve.
 10. A float valve as set forth in claim 9wherein said back pressure diaphragm seals off said outlet pipe as wellas opens said air ports when in its third attitude, seals off said airports and opens said outlet pipe to said main port in its secondattitude, and seals both said outlet pipe and said air ports from saidmain port in its first attitude.
 11. A float vavle as set forth in claim7 including structure within said housing defining two intermediatechambers into which water flow from said main port is discharged thewater flowing from said main port into said first intermediate chamberand then through said second intermediate chamber in sequence, and saidback pressure valve being located at the outlet of said secondintermediate chamber, and at least one orifice communicating betweensaid first and second intermediate chambers to allow water flowtherebetween, said port providing a third pressure drop orifice inaddition to the pressure drop orifices provided at said main port andback pressure valve so that water noise is substantially eliminated aswater flows through the float valve.
 12. A float vavle as set forth inclaim 11 wherein said two tubular intermediate chambers are locatedaxially and concentrically within said housing, the water flow to saidmain port being in an annular flow which is transformed to alongitudinal flow after it passes through said main port, and the waterflow to said back pressure valve being a longitudinal flow which istransformed into an annular flow as it exhausts from said back pressurevalve.